There's a whole bunch of people who use m4/3 cameras as a cheap alternative to Leica, but they still want the fast glass. If anything, using the screen is better than a SLR style optical viewfinder at this point, as you can never see the DoF adequately in the viewfinder when it is ultra-shallow.

There's also the manual focus assist (which ironically would have to be triggered manually on this lens, so it's a manual manual focus assist ) which magnifies part of the image, thus making it relatively easy to confirm focus even on the EVF or LCD.